Three times within six months, the inbox in my wife's Thunderbird email has emptied, without warning. While writing a message, her work and all read and unread email in the inbox has simply vanished. All other folders have remained intact.

I have not had the same problem. We both have Windows 7 64-bit in Intel Core 2 systems, mine perhaps a bit more robust but basically similar.

A dozen or more posters to a Thunderbird support forum have reported the same problem. Remedies have been suggested, but all have failed. Just thought I'd try here....

More details may help get an answer. What type of email, pop3 or IMAP, which email server, etc. etc.

No sure what details to give - Pop email server (don't know if it's pop3 or?), Shaw email server - It's unlikely any of the others having the problem are on Shaw.... anyway don't worry about it, there doesn't seem to be an answer available. I've been able to restore most of her email from a continuous backup, set up a couple of months ago....

You don't specify what fixes were suggested so forgive me if you've already tried this one:
1) close TB
2) locate and delete the file called Inbox.msf
3) restart TB
NB it HAS to be the file called 'Inbox.msf' NOT, most definitely NOT the file just called 'Inbox', with no extension.

The .msf file is the Message Summary File and it is this file that TB uses to display the contents of the Inbox file without the extension in the TB user interface. If the .msf file becomes corrupt the contents of the Inbox seem to disappear or be incomplete. If the .msf file is not present TB will recreate it when it starts.

Thanks, Star lounger. It's been a while - I tried many things but I can't remember if I tried deleting Inbox.msf - I was able to restore nearly all of her email from Rebit backup - but that's definitely something to try the next time it happens. Which I expect it will, sooner or later....
Thanks again....

Just a sidebar here, but these sorts of lost e-mail issues do not require any special backup software.

In each computer user's Application Data folder, there is a sub-folder called Thunderbird. Everything you need to run Thunderbird for that user is there. I just copy that folder to an external drive once in awhile, and if anything goes flakey with T-Bird, just delete the Thunderbird Application Data folder, and replace it with the backup copy. I've gotten out of several Eudora/Thunderbird jams that way (My e-mail client has the Eudora/Penelope skin, but it's basically Thunderbird under the hood.) As long as the backup data are not unstable, the restored Thunderbird will be as good as new, and the disappearing e-mail problems should go away for awhile.

There is a practical limit as to how much mail can be stored in the Thunderbird inbox without losing all or part of it. I have never reached that limit, but I use Local Folders to archive older mail. Those folders almost never lose messages. Compacting the folders and emptying the trash once in awhile seems also to help a bit with stability. But having the full application data folder backed up seems to be the best strategy, in my experience.

(For those who do use IMAP, remember, ONLY your Local Folders are not synced with the remote server in this type of e-mail scheme. That means that for IMAP, maintaining separate Local Folders is ESSENTIAL! I learned that the hard way.)

Another thing I recommend is to limit how many Extensions you plug into T-Bird.

Thanks. Good points. However, there are other good reasons for having a full continuous backup.

I agree on Local Folders. They are invaluable for keeping safe important emails or old messages that you just don't want to lose! After all, I do like to clear out a pile of old email every six months or so....

I have been using Thunderbird for a year or more and have had the problem of disappearing Inbox messages many times. As described above, the 'standard' solution is to delete the Inbox.msf file and open Thunderbird again. However, sometimes that doesn't work. There are two things to do:

1. Reboot the PC to make sure Thunderbird is not still running. Under some circumstances, if you close Thunderbird it doesn't actually close but just goes invisible! Rebooting makes sure it really is closed. Then delete the Inbox.msf file again and open Thunderbird again. If that doesn't solve the problem or if your Inbox file is empty, follow the suggestion below.

2. Open Thunderbird and look for a folder named nstmp or nstmp-1, etc. in the folder list on the the left in the Thunderbird window. I always find one or more of those folders listed there after an Inbox failure and they always contain the missing Inbox messages! If you have more than one of those folders pick the one whose contents looks the best and drag those messages into the Inbox. After the Inbox is working properly again, delete all the nstmp* folders in Thunderbird.

The Following 2 Users Say Thank You to BillWilson For This Useful Post:

nstmp folders appear when TB's folder compacting goes awry. Often when the folder in question has lots & lots of messages in it and so compacting takes a long time.

My experience is that average users tend to dismiss TB's request to 'compact folders'. Probably because the default 'compact folders when it will save over 1000 kB' is a bit conservative [Tools|Options|Advanced] and so nags then too often. That then of course compounds the length of time it does take to compact folders and make it more likely it will fail. Especially when, despite my pleas to file/delete messages as they deal with them, I find users with thousands of messages in their Inbox. (them: "Yes, now that you mention it my email does seem a bit slow", me: )

nstmp folders appear when TB's folder compacting goes awry. Often when the folder in question has lots & lots of messages in it and so compacting takes a long time.

My experience is that average users tend to dismiss TB's request to 'compact folders'. Probably because the default 'compact folders when it will save over 1000 kB' is a bit conservative [Tools|Options|Advanced] and so nags then too often. That then of course compounds the length of time it does take to compact folders and make it more likely it will fail. Especially when, despite my pleas to file/delete messages as they deal with them, I find users with thousands of messages in their Inbox. (them: "Yes, now that you mention it my email does seem a bit slow", me: )

stuck

I hadn't thought of that. You see, I am one of those e-mail users who will create about a million Local Folders, and then file each e-mail as it becomes about a week old. Google g-mail encourages the exact opposite behavior, and this has carried over into many users' (mis-)use of Thunderbird. Folks, the Folders are there for a reason, and the most useful one is TRASH! (And Empty Trash is also vitally important.)